Radiation control in a limiter tokamak

The requirements for radiation cooling in a tokamak are discussed and experimental evidence for a plasma with a cold radiating boundary - the detached plasma - is presented as an example. The radiation characteristics is analyzed and, in particular, the non-coronal conditions at the plasma boundary are considered by introducing the radiation potential in order to express the radiation in terms of impurity fluxes rather than in densities. The possibilities for radiation control by intrinsic and injected impurities are examined and some experimental examples are presented. (orig.)